a Robert Heinlein style authoritative white guy hero/author stand-in with the fucking absolute stiffest of upper lips, and probably also a Jacob Rees-Mogg style monocle - let's just say it's actually JRM, but Peter Thiel has turned him into an immortal cyborg - emerges to lead a resistance to this new Dark Age. the remaining British people band together in the greatest example of Churchillian Dunkirk Spirit in all of human history to throw off their merciless metric overlords. cyborg JRM fires a nuclear missile into the sun which [somehow, science handwave] reverses global cooling. everywhere pubs reopen, footballs are emphatically kicked, Britain is once again a green and pleasant land.
but wait! plot twist: in their dying the moments the Boygirl-Eurocrat alliance has sent the ultimate assassin - a genetically engineered combination [more scientific handwave] of all races, sexes, and sexual orientations, like T-1000 if its superpower was codeswitching instead of shapeshifting - back in time to assassinate JRM as a tween in early 80s London. fortunately the resistance was able to send JRM's grandson - Kyle Rees - back in time as well. that's right, it's just an elaborate excuse for yet another Terminator reboot.
Terminator X: An American Terminator In London. "This time it's in England, bitches" (I'm open to more culturally specific taglines)